Preparation method of circuit board with heat dissipation function

Abstract

A method for preparing a circuit board includes the following steps: stacking a first peelable film and a second peelable film, and laying velvet carbon nanotubes between the first peelable film and the second peelable film to form a carbon nanotube layer; pressing the first peelable film, the carbon nanotube layer and the second peelable film to compact the velvet carbon nanotubes to obtain a heat-conducting layer; removing the first peelable film, and forming a first glue layer, a first dielectric layer and a first circuit layer on the side of the heat-conducting layer away from the second peelable film; removing the second peelable film, and forming a second glue layer, a second dielectric layer and a second circuit layer on the side of the heat-conducting layer away from the first glue layer; and installing electronic components on the first circuit layer. The present application can quickly dissipate the heat generated by the electronic components, and the preparation process is simple, with low energy consumption and cost.

Description

Technical Field

[0001] The present application relates to the field of circuit boards, and in particular to a method for preparing a circuit board with heat dissipation function. Background Art

[0002] A circuit board generally includes a circuit substrate and electronic components mounted on the circuit substrate. As electronic devices develop towards multifunctionality, the number of electronic components integrated on the circuit board also increases. However, since electronic components generate heat during operation, if the heat cannot be dissipated in time, the circuit substrate may be deformed or even damaged, resulting in the circuit board not being able to work properly. Summary of the invention

[0003] In order to solve the above shortcomings of the prior art, it is necessary to propose a method for preparing a circuit board.

[0004] The present application provides a method for preparing a circuit board, comprising the following steps: stacking a first peelable film and a second peelable film, and laying velvet-like carbon nanotubes between the first peelable film and the second peelable film to form a carbon nanotube layer; pressing the first peelable film, the carbon nanotube layer and the second peelable film to compact the velvet-like carbon nanotubes to obtain a heat-conducting layer; removing the first peelable film, and forming a first glue layer, a first dielectric layer and a first circuit layer on a side of the heat-conducting layer away from the second peelable film; removing the second peelable film, and forming a second glue layer, a second dielectric layer and a second circuit layer on a side of the heat-conducting layer away from the first glue layer; and installing electronic components on the first circuit layer to obtain the circuit board.

[0005] In some possible implementations, forming the first adhesive layer, the first dielectric layer and the first circuit layer on the side of the thermally conductive layer away from the second peelable film specifically includes: providing a first copper clad substrate, the first copper clad substrate including a first adhesive layer, a first dielectric layer and a first copper foil layer stacked in sequence; stacking the first copper clad substrate on the side of the thermally conductive layer away from the second peelable film, so that the thermally conductive layer is arranged between the first adhesive layer and the second peelable film; pressing the first copper clad substrate, the thermally conductive layer and the second peelable film; etching the first copper foil layer to obtain the first circuit layer.

[0006] In some possible implementations, forming the first adhesive layer, the first dielectric layer and the first circuit layer on the side of the thermally conductive layer away from the second peelable film specifically includes: providing a second copper clad substrate, the second copper clad substrate including a second adhesive layer, a second dielectric layer and a second copper foil layer stacked in sequence; removing the second peelable film so that the thermally conductive layer is arranged between the first adhesive layer and the second adhesive layer; pressing the second copper clad substrate, the thermally conductive layer and the first copper clad substrate; etching the second copper foil layer to obtain the second circuit layer.

[0007] In some possible implementations, a first alignment hole and a second alignment hole are respectively provided in the first peelable film and the second peelable film. After the first peelable film and the second peelable film are stacked, the first alignment hole and the second alignment hole correspond to each other. Before pressing the first peelable film, the carbon nanotube layer and the second peelable film, the method further includes: passing a positioning column through the first alignment hole, the thermal conductive layer and the second alignment hole.

[0008] In some possible implementations, the first circuit layer includes at least two solder pads, and the electronic component is soldered to the solder pads via solder balls.

[0009] In some possible implementations, after installing the electronic component, the method further includes: bending the circuit board.

[0010] In the present application, the heat generated by the electronic components during use can be successively conducted to the first dielectric layer and the heat-conducting layer along the thickness direction of the circuit board. The velvety carbon nanotubes in the heat-conducting layer can be used as a heat dissipation medium to dissipate the heat generated by the electronic components to the outside world, thereby meeting the heat dissipation requirements of the circuit board. Moreover, the velvety carbon nanotubes are soft in material, which is beneficial to improving the flexibility of the circuit board. In addition, the present application prepares the velvety carbon nanotubes as a heat-conducting layer after lamination. Since the velvety carbon nanotubes are soft in material, they can extend along the surface of the first peelable film or the second peelable film during lamination, so that the velvety carbon nanotubes are more evenly distributed in the heat-conducting layer formed after lamination. Compared with the solution of attaching a catalyst to the surface of the peelable film, placing it in a high-temperature reactor and introducing a reaction gas to prepare a carbon heat-conducting layer, the present application can complete the preparation of the heat-conducting layer through a lamination process, with a simple process and low energy consumption and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of velvety carbon nanotubes provided in accordance with one embodiment of the present application.

[0012] Figure 2 For the general Figure 1 The schematic diagram shown is that velvety carbon nanotubes are laid between the first insulating layer and the second insulating layer.

[0013] Figure 3For pressing Figure 2 Schematic diagram of forming velvety carbon nanotubes to obtain a thermally conductive layer.

[0014] Figure 4 This is a schematic diagram of the first copper-clad substrate provided in this application.

[0015] Figure 5 To remove Figure 3 Schematic diagram after the first insulation layer is shown.

[0016] Figure 6 For the general Figure 4 The first copper-clad substrate shown is pressed onto Figure 5 Schematic diagram of the thermal conductive layer shown.

[0017] Figure 7 This is a schematic diagram of the second copper-clad substrate provided in this application.

[0018] Figure 8 To remove Figure 6 Schematic diagram after the second insulation layer is shown.

[0019] Fig. 9 For the general Figure 7 The second copper clad substrate shown is pressed onto Figure 8 Schematic diagram of the thermal conductive layer shown.

[0020] Fig.10 For etching Fig. 9 The schematic diagram of the first copper foil layer and the second copper foil layer after obtaining the first circuit layer and the second circuit layer is shown.

[0021] Fig.11 For Fig.10 A schematic diagram of a circuit board obtained after electronic components are installed on the first circuit layer shown.

[0022] Fig.12 For the general Fig.11 Schematic diagram of the circuit board after bending.

[0023] Main component symbols

[0024] Fleece-like carbon nanotubes 10

[0025] Carbon nanotube layer 11

[0026] Thermal conductive layer 12

[0027] First peelable film 20

[0028] Second peelable film 21

[0029] Positioning column 22

[0030] The first copper-clad substrate 30

[0031] First adhesive layer 31

[0032] First dielectric layer 32

[0033] The first copper foil layer 33

[0034] The second copper-clad substrate 40

[0035] Second adhesive layer 41

[0036] The second dielectric layer 42

[0037] The second copper foil layer 43

[0038] The first circuit layer 50

[0039] Second circuit layer 51

[0040] Electronic components 60

[0041] Solder ball 61

[0042] Circuit board 100

[0043] The first alignment hole 201

[0044] The second alignment hole 211

[0045] Solder pad 501

[0046] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned purposes, features and advantages of the embodiments of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the features in the implementation methods of the present application can be combined with each other without conflict.

[0048] In the following description, many specific details are set forth to facilitate a full understanding of the embodiments of the present application. The described implementation methods are only part of the implementation methods of the present application, rather than all of the implementation methods.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the technical field of the embodiments of the present application. The terms used in the specification of the present application are only for the purpose of describing specific implementation methods and are not intended to limit the embodiments of the present application.

[0050] An embodiment of the present application provides a method for preparing a circuit board, comprising the following steps:

[0051] S1, see Figure 1 , providing velvety carbon nanotubes 10.

[0052] In some embodiments, the particle size of the velvet carbon nanotubes 10 is up to 70 mm. The velvet carbon nanotubes 10 can be prepared by in-situ floating catalyst chemical vapor deposition (FC-CVD), hydrothermal method or photocatalytic degradation method.

[0053] S2, see Figure 2 , providing a first peelable film 20 and a second peelable film 21. The first peelable film 20 and the second peelable film 21 are stacked, and the fleece-like carbon nanotubes 10 are laid between the first peelable film 20 and the second peelable film 21 to form a carbon nanotube layer 11.

[0054] In some embodiments, the materials of the first peelable film 20 and the second peelable film 21 are both insulating resins. Specifically, the materials of the first peelable film 20 and the second peelable film 21 can be selected from one of epoxy resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). The materials of the first peelable film 20 and the second peelable film 21 can be the same or different.

[0055] S3, see Figure 3 , the first peelable film 20, the carbon nanotube layer 11 and the second peelable film 21 are pressed together, thereby compacting the velvety carbon nanotubes 10 in the carbon nanotube layer 11 to obtain the thermal conductive layer 12. That is, the gaps between the velvety carbon nanotubes 10 in the carbon nanotube layer 11 are reduced after pressing. That is, the velvety carbon nanotubes 10 are transformed from a relatively fluffy state to a relatively dense state.

[0056] Please refer to Figure 2 and Figure 3 In some embodiments, the first peelable film 20 and the second peelable film 21 are respectively provided with a first alignment hole 201 and a second alignment hole 211. After the first peelable film 20 and the second peelable film 21 are stacked, the first alignment hole 201 and the second alignment hole 211 correspond to each other. Before the first peelable film 20, the carbon nanotube layer 11 and the second peelable film 21 are pressed together, the positioning post 22 is first passed through the first alignment hole 201, the heat conductive layer 12 and the second alignment hole 211, and then pressed together. The positioning post 22 is used to ensure that the pressure during pressing is set along the direction of the positioning post 22.

[0057] S4, see Figure 4, providing a first copper clad substrate 30. The first copper clad substrate 30 includes a first adhesive layer 31, a first dielectric layer 32 and a first copper foil layer 33 stacked in sequence.

[0058] In some embodiments, the material of the first dielectric layer 32 is insulating resin. Specifically, the material of the first dielectric layer 32 can be selected from epoxy resin, polypropylene, BT resin, polyphenylene ether, polyimide, polyethylene terephthalate, polyethylene naphthalate and other resins.

[0059] In some embodiments, the material of the first adhesive layer 31 can be existing pure adhesive.

[0060] S5, see Figure 5 and Figure 6 , remove the first peelable film 20 , and stack the first copper clad substrate 30 on the side of the thermal conductive layer 12 away from the second peelable film 21 , so that the thermal conductive layer 12 is disposed between the first adhesive layer 31 and the second peelable film 21 .

[0061] Before removing the first peelable film 20 , the positioning post 22 is first removed.

[0062] S6, see Figure 6 , the first copper clad substrate 30 , the heat conductive layer 12 and the second peelable film 21 are pressed together, so that the heat conductive layer 12 and the first adhesive layer 31 are bonded together.

[0063] The first adhesive layer 31 is used to bond together the part of the fleece-like carbon nanotubes 10 in the heat-conducting layer 12 close to the first adhesive layer 31 for fixation.

[0064] S7, see Figure 7 , providing a second copper clad substrate 40. The second copper clad substrate 40 includes a second glue layer 41, a second dielectric layer 42 and a second copper foil layer 43 stacked in sequence.

[0065] In some embodiments, the material of the second dielectric layer 42 is an insulating resin. Specifically, the material of the second dielectric layer 42 can be selected from one of epoxy resin, polypropylene, BT resin, polyphenylene ether, polyimide, polyethylene terephthalate, polyethylene naphthalate, etc. The material of the second dielectric layer 42 and the first dielectric layer 32 can be the same or different.

[0066] In some embodiments, the material of the second adhesive layer 41 may be existing pure adhesive. The material of the second adhesive layer 41 and the first adhesive layer 31 may be the same or different.

[0067] S8, see Figure 8 and Fig. 9, remove the second peelable film 21 , and laminate the second copper clad substrate 40 on the side of the thermal conductive layer 12 away from the first adhesive layer 31 , so that the thermal conductive layer 12 is disposed between the first adhesive layer 31 and the second adhesive layer 41 .

[0068] S9, see Fig. 9 , the second copper clad substrate 40 , the heat conductive layer 12 and the first copper clad substrate 30 are pressed together, so that the heat conductive layer 12 and the second adhesive layer 41 are bonded together.

[0069] The second adhesive layer 41 is used to bond together a portion of the fleece-like carbon nanotubes 10 in the heat-conducting layer 12 close to the second adhesive layer 41 to prevent them from falling off.

[0070] S10, see Fig.10 , the first copper foil layer 33 and the second copper foil layer 43 are etched to obtain a first circuit layer 50 and a second circuit layer 51 respectively. The first circuit layer 50 includes at least two pads 501 .

[0071] In some embodiments, the first circuit layer 50 and the second circuit layer 51 can be prepared by exposure and development. Specifically, the exposure and development includes the steps of lamination, exposure, development, etching, and film removal.

[0072] S11, see Fig.11 , electronic components 60 are mounted on the pads 501 to obtain the circuit board 100 .

[0073] In some embodiments, the electronic component 60 may be soldered to the solder pad 501 via the solder balls 61 .

[0074] S12, see Fig.12 , the circuit board 100 is bent into a desired shape so that the circuit board 100 can be installed on a curved surface. That is, the circuit board 100 is a flexible circuit board.

[0075] When in use, the heat generated by the electronic component 60 can be successively conducted to the first dielectric layer 32 and the thermal conductive layer 12 via the solder pad 501 along the thickness direction of the circuit board. The thermal conductive layer 12 is provided with velvety carbon nanotubes 10, which can be used as a heat dissipation medium to dissipate the heat generated by the electronic component 60 to the outside, thereby meeting the heat dissipation requirements of the circuit board 100. Among them, due to the grain orientation of the velvety carbon nanotubes 10, the velvety carbon nanotubes 10 can evenly conduct heat along two directions of the plane where the thermal conductive layer 12 is located, so as to quickly and evenly conduct heat to various positions of the thermal conductive layer 12 and dissipate it outward. Moreover, the velvety carbon nanotubes 10 are made of a relatively soft material, which is conducive to improving the flexibility of the circuit board.

[0076] In addition, the present application prepares the velvet carbon nanotubes 10 into a heat-conducting layer 12 after lamination. Since the velvet carbon nanotubes 10 are made of a relatively soft material, they can extend along the surface of the first peelable film 20 or the second peelable film 21 during lamination, so that the velvet carbon nanotubes 10 are evenly distributed in the heat-conducting layer 12 formed after lamination. Compared with the solution of attaching a catalyst to the surface of the peelable film, placing it in a high-temperature reactor and introducing a reaction gas to prepare the carbon heat-conducting layer 12, the present application can complete the preparation of the heat-conducting layer 12 through a lamination process, which has a simple process and low energy consumption and cost.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A method for preparing a circuit board, characterized in that: The steps include: A first peelable film and a second peelable film are stacked and arranged, and fleece-like carbon nanotubes are laid between the first peelable film and the second peelable film to form a carbon nanotube layer, wherein a first alignment hole and a second alignment hole are respectively provided through the first peelable film and the second peelable film, and the first alignment hole corresponds to the second alignment hole; The first peelable film, the carbon nanotube layer and the second peelable film are pressed together, thereby compacting the fleece-like carbon nanotubes to obtain a heat-conducting layer, wherein before pressing together the first peelable film, the carbon nanotube layer and the second peelable film, a positioning post is passed through the first alignment hole, the heat-conducting layer and the second alignment hole, and the positioning post is used to set the pressure during pressing along the direction of the positioning post; Removing the first peelable film, and forming a first glue layer, a first dielectric layer and a first circuit layer on a side of the thermal conductive layer away from the second peelable film; Removing the second peelable film, and forming a second glue layer, a second dielectric layer, and a second circuit layer on a side of the heat conductive layer away from the first glue layer; Electronic components are mounted on the first circuit layer to obtain the circuit board.

2. The method for preparing a circuit board according to claim 1, characterized in that: Forming the first adhesive layer, the first dielectric layer and the first circuit layer on a side of the heat conductive layer away from the second strippable film specifically includes: Providing a first copper-clad substrate, wherein the first copper-clad substrate comprises a first adhesive layer, a first dielectric layer and a first copper foil layer stacked in sequence; Laminating the first copper clad substrate on a side of the heat conductive layer away from the second peelable film, so that the heat conductive layer is disposed between the first adhesive layer and the second peelable film; Laminating the first copper-clad substrate, the heat-conducting layer and the second peelable film; The first copper foil layer is etched to obtain the first circuit layer.

3. The method for preparing a circuit board according to claim 2, characterized in that: Forming the first adhesive layer, the first dielectric layer and the first circuit layer on a side of the heat conductive layer away from the second strippable film specifically includes: Providing a second copper-clad substrate, wherein the second copper-clad substrate comprises a second adhesive layer, a second dielectric layer, and a second copper foil layer stacked in sequence; removing the second peelable film so that the heat conductive layer is disposed between the first adhesive layer and the second adhesive layer; Laminating the second copper-clad substrate, the heat-conducting layer and the first copper-clad substrate; The second copper foil layer is etched to obtain the second circuit layer.

4. The method for preparing a circuit board according to claim 1, characterized in that: The particle size of the fleece-like carbon nanotubes is 70 mm.

5. The method for preparing a circuit board according to claim 1, characterized in that: The first circuit layer includes at least two solder pads, and the electronic components are soldered to the solder pads via solder balls.

6. The method for preparing a circuit board according to claim 1, characterized in that: After installing the electronic component, the method further comprises: The circuit board is bent.

Images